MLA

Kissinger, Henry, 1923-2023. Correspondence. Box 131, folder 6. 1956-1957 January. https://collections.library.yale.edu/catalog/11784653.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 131, folder 6"])(1956-1957 January)[Correspondence]. https://collections.library.yale.edu/catalog/11784653.